Modular wireless communications platform

ABSTRACT

A modular wireless communications platform is provided. The modular wireless communications platform has a modular host unit and a modular remote unit in communication with the modular host unit. The modular host unit and remote unit include a serial radio frequency communicator configured to convert serial digital data into RF sampled data and configured to convert RF sampled data into serial digital data. The modular host unit and remote unit also include an interface coupled to the serial radio frequency communicator and configured to allow transfer of the RF sampled data from the serial radio frequency communicator to a digital to analog radio frequency transceiver module.

RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 11/627,251 (hereafter the “'251 Application”), entitled“MODULAR WIRELESS COMMUNICATIONS PLATFORM”, filed on Jan. 25, 2007,which is hereby incorporated herein by reference. The presentapplication hereby claims the benefit of priority of the '251Application.

BACKGROUND

Technology is continually evolving as consumer needs change and newideas are developed. Nowhere is this more apparent than in the wirelesscommunications industry. Wireless communication technologies havechanged drastically over the recent past and have affected many aspectsof our daily lives. As new wireless technologies are developed,companies must invest large amounts of time and resources to upgrade alltheir existing hardware so that it is compatible with the newtechnology. Often a change in one component of a system requires anupdate of the entire system.

The infrastructure of a wireless communication system is commonlydesigned for a specific technology and a specific frequency band. Thus,once a service provider installs a particular infrastructure, a completeoverhaul of a system is required to upgrade to a new technology orchange to another frequency band. In addition, if a service providerwould like to carry multiple frequency bands, the provider generally hasto install a different set of hardware for each technology and frequencyband carried. Thus, if the service provider carries four frequency bandsof service for mobile customers; four different sets of hardware must beinstalled in each transmission and reception location.

In addition to changes in technology, consumer demand for a particularservice may change after a service is installed. For example, accesspoints initially deployed using over-the-air repeaters or simulcastdistributed antenna systems, may need to be replaced with full basestations to support the increased consumer demand. This again, willrequire major overhauls of existing infrastructure. Moreover, thesechanges occur not infrequently, are costly and are often necessary tokeep pace with competitors within the industry.

For the reasons stated above, and for other reasons stated below whichwill become apparent to those skilled in the art upon reading andunderstanding the present specification, there is a need in the art fora wireless communications platform that keeps pace with the rapidchanges in wireless communications protocols.

SUMMARY

The following summary is made by way of example and not by way oflimitation. It is merely provided to aid the reader in understandingsome of the aspects of the invention.

In one embodiment, a distributed antenna system is provided. Thedistributed antenna system includes a host unit and a remote unitcoupled to the host unit over a communication medium. The host unitincludes an interface adapted to communicate RF signals with an InternetProtocol (IP) gateway as IP data; a baseband processor, coupled to theIP gateway, the baseband processor configured to convert between IP dataand baseband, digital signals; and a serializer/deserializer, coupled tothe baseband processor, the serializer/deserializer configured toconvert between baseband, digital data and a serial data stream. Theremote unit includes a serializer/deserializer, coupled to thecommunication medium, the serializer/deserializer configured to convertbetween the serial data stream and RF sampled data; an RF module,coupled to the serializer/deserializer, the RF module configured toconvert between RF sampled data and an RF signal; and an antenna coupledto the RF module.

In another embodiment, another distributed antenna system is provided.This distributed antenna system includes a host unit and a remote unitcoupled to the host unit over the communication medium. The host unitincludes an RF module configured to communicate with a base stationusing RF signals configured for communication over an antenna, the RFmodule configured to convert between the RF signals configured forcommunication over an antenna and RF sampled data; aserializer/deserializer coupled to the RF module and configured tocommunicate with a base station using signals corresponding to baseband,digital data, the serializer/deserializer configured to convert betweenRF sampled data and first serial data and configured to convert betweenbaseband, digital data and second serial data; and a multiplex modulecoupled to the serializer/deserializer, the multiplex module configuredto multiplex the first serial data and the second serial data into ahigh speed serial data stream and to demultiplex a high speed serialdata stream into the first serial data and the second serial data. Theremote unit is configured to convert the high speed serial data streaminto one or more RF signals.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention can be more easily understood and furtheradvantages and uses thereof more readily apparent, when considered inview of the detailed description and the following figures in which:

FIG. 1 is an illustration of one embodiment of a system using a modularwireless communications platform;

FIG. 2 illustrates a schematic view of one embodiment of a host unit foruse in the system of FIG. 1;

FIG. 3 illustrates a schematic view of one embodiment of a remote unitfor use in the system of FIG. 1;

FIG. 4 illustrates a schematic view of one embodiment of a digital toanalog radio frequency transceiver module for use in either the hostunit of FIG. 2 or the remote unit of FIG. 3;

FIG. 5 illustrates a schematic view of one embodiment of a serial radiofrequency communicator for use in either the host unit of FIG. 2 or theremote unit of FIG. 3;

FIG. 6 illustrates another configuration of the system of FIG. 1;

FIG. 7 illustrates yet another configuration of the system of FIG. 1;

FIG. 8 illustrates one embodiment of a distributed base station system;and

FIG. 9 illustrates another embodiment of a distributed base stationsystem.

In accordance with common practice, the various described features arenot drawn to scale but are drawn to emphasize specific features relevantto the present invention. Reference characters denote like elementsthroughout Figures and text.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings that form a part hereof, and in which is shown byway of illustration specific illustrative embodiments in which thedevice may be practiced. These embodiments are described in sufficientdetail to enable those skilled in the art to practice the invention, andit is to be understood that other embodiments may be utilized and thatlogical, mechanical and electrical changes may be made without departingfrom the spirit and scope of the present invention. The followingdetailed description is, therefore, not to be taken in a limiting sense.

The present apparatus is a modular wireless platform that enables asystem facilitator to easily and inexpensively adapt their wirelesssystem for use with different data transport mechanisms, frequencybands, communication technologies, and intelligence distribution. Thismodular platform is made up of a reconfigurable host unit and areconfigurable remote unit designed for use in a system with a centralnode and a plurality of distributed antennas. The host unit is locatednear the central node and facilitates transmission/reception ofinformation to/from the remote units which are located remotely with anaccompanying antenna. The remote units function to transmit/receivetransmissions from the host unit and transmit/receive wireless signalsover accompanying antenna to mobile costumers.

Host unit and remote unit have a modular design and defined interfacesthat allow components to be removed and installed to adapt to the needsof the service providers. Both host and remote unit are designed arounda serial radio frequency (SeRF) communicator and have a definedinterface where different varieties of digital to analog radio frequencytransceiver (DART) modules can be connected and disconnected. There aremany different DART modules, and each DART module is designed for aparticular technology and frequency band. Thus, technology and frequencyband adjustments can be made by simply replacing the DART module in thehost unit or remote unit. Additionally, host unit and remote unit aredesigned to allow different transport mechanisms between the host unitand remote unit. For example, the same host unit and remote unit thatuse fiber optic for inter-unit transmission can be adapted to use E Bandwireless transmission instead of or concurrently with the fiber optic.Finally, wireless processing functionality can be placed all on a basestation near the central node, or the functionality can be distributedthroughout each of the remote units. The flexibility to modify thefunctionality of each remote unit allows the wireless platform tosupport centralized base stations and distributed base stations, eitherseparately or concurrently.

FIG. 1 is a block diagram of one embodiment of a system 100 using amodular wireless communications platform. System 100 is a fieldconfigurable distributed antenna system (DAS) that providesbidirectional transport of a fixed portion of RF spectrum from anInternet Protocol (IP) gateway 101 to a remote antenna 108. Along withIP gateway 101 and remote antenna 108, system 100 includes a basestation 103, a host unit 102, a transport mechanism 104, and a remoteunit 106. Host unit 102, a modular host transceiver and remote unit 106,a modular remote radio head, work together to transmit and receive datato/from remote antennas. In this embodiment, host unit 102 provides theinterface between a base station 101 a signal transport mechanism 104.Remote unit 106 provides the interface between transport mechanism 104and a remote antenna 108. In this embodiment, signal transport mechanism104 is an optical fiber, and host unit 102 sends optical signals throughthe optical fiber to remote unit 106.

In the transmission direction of transport, base station 103 performsbaseband processing on IP data from IP gateway and places the IP dataonto a channel. In one embodiment base station 103 is an IEEE 802.16compliant base station. Optionally, base station 103 may also meet therequirements of WiMax, WiBro, or a similar consortium. In anotherembodiment, base station 103 is an 800 MHz or 1900 MHz base station. Inyet another embodiment, the system is a cellular/PCS system and basestation 103 communicates with a base station controller. In stillanother embodiment, base station 103 communicates with a voice/PSTNgateway. Base station 103 also creates the protocol and modulation typefor the channel. Base station 103 then converts the IP packetized datainto an analog RF signal for transmission over antenna 108. Base station103 sends the RF signal to host unit 102. Host unit 102 converts the RFsignal for long distance high speed transmission over transportmechanism 104. Host unit 102 sends the signal over transport mechanism104, and the signal is received by remote unit 106. Remote unit 106converts the received signal back into an RF signal and transmits thesignal over antenna 108 to consumer mobile devices.

FIG. 2 illustrates a schematic diagram of one embodiment of a host unit102 for use in a modular wireless communications platform. Host unit 102has a serial radio frequency (SeRF) communicator 202 that is coupled toa digital to analog radio frequency transceiver (DART) interface 204.DART interface 204 has a plurality of DART connectors each of which isconfigured to receive a pluggable DART module 208. Further, DARTconnectors are configured to connect DART module 208 to SeRFcommunicator 202. DART interface 204 is a common interface that isconfigured to allow communication between SeRF communicator 202 anddifferent varieties of DART modules 208. Additionally, DART interface204 allows multiple DART modules 208, 210, 212 to connect to a singleSeRF communicator 202. In this embodiment, DART interface 204 is apassive host backplane to which SeRF communicator 202 also connects. Inthis embodiment, DART interface 204 has eight DART connectors for a DARTmodule 208. In another embodiment, instead of being a host backplane,DART interface 204 is integrated with SeRF communicator 202.

DART modules 208, 210, 212 provide bi-directional conversion to/fromanalog RF signals from/to digital sampled RF. In one direction ofcommunication, DART module 208 receives an incoming analog RF signalfrom base station 103 and converts the analog signal to a digital signalfor use by SeRF communicator 202. In the other direction DART modules208, 210, 212 receive digital sampled RF data from SeRF communicator 202and convert the data to analog RF for use by base station 103.

Each DART module 208, 210, 212 has a common communication interface forcommunication with SeRF communicator 202, and a RF processing portionthat is exclusive to one frequency band and communication technology.Each DART module 208, 210, 212, therefore, converts to/from one analogRF to the digital signal used by SeRF communicator. For example, DARTmodule 208 is designed to transmit 850 MHz cellular transmissions. Asanother example, DART module 210 transmits 1900 MHz PCS signals. Some ofthe other options for DART modules 208, 210, 212 include Nextel 800band, Nextel 900 band, PCS full band, PCS half band, BRS, WiMax, and theEuropean GSM 900, DCS 1800, and UMTS 2100. By allowing differentvarieties of DART modules 208, 210, 212 to be plugged into DARTinterface 206, host unit 102 is configurable to any of the abovefrequency bands and technologies as well as any new technologies orfrequency bands that are developed. Host unit 102, once installed, isfield configurable to transmit a variety desired by insertion of adifferent DART module. Additionally, since SeRF communicator 202 isconfigured to communicate with multiple different DART modules 208, 210,212, a single host unit 102 can transmit/receive multiple frequencybands or technologies.

SeRF communicator 202 provides bi-directional conversion to/from a SeRFstream from/to a high speed optical serial data stream. In onedirection, SeRF communicator 202 receives incoming SeRF streams fromDART modules 208, 210, 212 and sends a serial optical data stream overtransport mechanism 104 to remote unit 106. In the other direction, SeRFcommunicator 202 receives an optical serial data stream from a remoteunit 106 and provides SeRF streams to DART modules 208, 210, 212. In oneembodiment, the SeRF stream between DART module 208 and SeRFcommunicator is a parallel stream. In another embodiment, SeRF stream isa serial data stream.

SeRF communicator 202 also allows multiple DART modules 208, 210, 212 tooperate in parallel. SeRF communicator 202 actively multiplexes thesignals from each DART module 208, 210, 212 such that they are sentsimultaneously over a single transport mechanism 104. To accomplishthis, SeRF communicator 202 presents a clock signal to each DART module208, 210, 212 to ensure synchronization.

In one embodiment, an optical multiplex module 214 is optically coupledto SeRF communicator 202. Optical multiplex module 214 performsmultiplexing/de-multiplexing of an optical serial data stream to/fromSeRF communicator 202 over transport mechanism 104. In this embodiment,optical multiplex module 214 performs wavelength division multiplexing.

In another embodiment, transport mechanism 104 is a wireless millimeterwave signal transceiver (e.g. E Band/70 GHz radio). In this embodiment,host unit 102 sends optical signals to the millimeter wave transceiverwhich converts the optical signals into millimeter waves and transmitsthe millimeter waves to a similar millimeter wave transceiver connectedto remote unit 106. In yet another embodiment, transport mechanism 104is a microwave radio transceiver. In still another embodiment, transportmechanism 104 is a T1 connection for transmission of IP data.

FIG. 3 is a schematic diagram of one embodiment of a remote unit 106 foruse in a modular wireless communications platform. Remote unit 106 has aSeRF communicator 302, a SeRF interface 304, at least one DART interface306. In this embodiment, DART modules 308, 309, 311, power amplified310, duplexer/linear amplifier 312, and optical multiplex module 314 areall installed in remote unit 106 which is connected to antenna 108.

SeRF communicator 302 is designed and performs similar to SeRFcommunicator 202 of host unit 102. Likewise, DART modules 308, 309, 311have the same features and design options as DART modules 208, 210, 212of host unit 102. There is a slight difference from host unit 102,however, in the manner in which SeRF communicator 302 and DART modules308, 309, 311 are connected. In this embodiment of remote unit 106, SeRFcommunicator 302 has a SeRF interface 304 which is used to link SeRFcommunicator to SeRF cables 305. SeRF cables 305 are used to allow DARTmodules 308, 309, 311 to be physically spaced from SeRF communicator 302and from other DART modules. SeRF cables 305 connect to DART interface306. DART modules 308 connected to DART interface 306 and communicatewith SeRF communicator 302 through DART interface 306 over SeRF cables305 and through SeRF interface 304. In another embodiment, SeRFinterface 304, and SeRF cables 305 are eliminated and DART interface 306is integrated into SeRF communicator 302.

DART modules 308 perform similar to DART module 208, except the ultimatedestination/origination of the signals to/from DART modules 308 isantenna 108 and not base station 101 as in host unit 102. Opticalmultiplex module 314 also performs similarly to optical multiplex module214 of host unit 102.

In the transmission direction, once a signal is converted to analog RFby DART module 308, the signal is sent through RF interface 322(explained below) to power amplifier 310. Power amplifier 310 amplifiesthe RF signal received from DART module 308 for output throughduplexer/linear amplifier 312 to antenna 108. Similar to DART modules308, 309, 311, power amplifier 310 is designed for a certain frequencyband and technology. Power amplifier 310 is, therefore, removable and isplugged into a power amplifier connector on remote unit 106 which isconfigured to receive power amplifier 310. Power amplifier connector isconfigured to couple power amplifier to duplexer/linear amplifier 312and to DART module 308. Power amplifier 310 also has an alarm andcontrol line that is connected to DART interface 306 for communicationto SeRF communicator 302.

Once the signal is amplified by power amplifier 310, duplexer/linearamplifier 312 provides duplexing of the signal which is necessary toconnect transmit and receive signals to a common antenna.Duplexer/linear amplifier 312 also provides low noise amplification ofreceived signals and rms power detection of incident and reflected RFpower in transmission signal. Similar to DART modules 308, 309, 311 andpower amplifier 310, duplexer/linear amplifier 312 is frequency band andtechnology specific, and is removable. Duplexer/linear amplifier 312plugs into a connector in remote unit 106 configured to receiveduplexer/linear amplifier 312. Furthermore, the connector is configuredto couple duplexer/linear amplifier 312 to power amplifier 310 and toantenna 108. Duplexer/linear amplifier 312 also has a control and alarmline that is connected to DART interface 320 for communication to SeRFcommunicator 302. In this embodiment, the frequency band and technologyallow use of a single power amplifier 310 and duplexer/linear amplifier318 by both DART module 308 and DART module 309. In this embodiment, aRF interface 322 is placed between power amplifier 310, duplexer/linearamplifier 312 and DART modules 308, 309. RF interface 322 provides RFsplitting/combining of the RF transmit and receive signals necessary toallow connection of two DART modules 308, 309 to a single poweramplifier 310 and duplexer/linear amplifier 312.

FIG. 4 shows a schematic view of one embodiment of a DART module 400 foruse in either host unit 102 or remote unit 106. There are multipleembodiments of DART module 400 as described above, however, the commonelements are described hereafter. DART module 400 has an edge connector402 for connection to a DART interface. DART module 400 has two mainsignal paths; a transmission path 404 and a reception path 406. Forsignals received from a SeRF communicator, DART module 400 formsparallel digital RF data from the incoming SeRF stream, if needed, atFPGA 403. In this embodiment, FPGA 403 is a logic device that isprogrammed to convert serial digital data into RF sampled data andprogrammed to convert RF sampled data into serial digital data. DARTmodule 400 then converts the digital signal to analog with digital toanalog converter (DAC) 408. Transmission path 404 continues as DARTmodule 400 filters, amplifies and up-converts the analog signal for RFtransmission with an assortment of filters 410, amplifiers 412, anoscillator 414, and an attenuator 416. The transmission path exits DARTmodule 400 at an SMA connector 420. The signals travel in the oppositedirection down reception path 406, where they are converted from analogto digital and sent to a SeRF communicator. First signals are receivedat SMA connector 420. DART module 400 then amplifies, down-converts,filters the incoming RF signal with a plurality of filters 410,amplifiers 412, oscillators 414, and attenuators 416. DART module 400then digitizes the signal with analog to digital converter 422. FPGA 403then forms a SeRF stream and provides the SeRF stream as paralleldigital RF sampled data to a SeRF communicator.

FIG. 5 illustrates a schematic view of one embodiment of a SeRFcommunicator 500 for use in either host unit 102 or remote unit 106.Serial radio frequency communicator 500 has a plurality of opticalinput/outputs 502, a clock 504, a field programmable gate array (FPGA)506, a plurality of DART links 508, and a processor 510. In thisembodiment, SeRF communicator 500 has eight (8) optical input/outputs502. Optical input/outputs 502 connect to optical fiber which is used asa transport mechanism, or optical fiber that links SeRF communicator 500to an optical multiplexer or a millimeter waver or microwavetransceiver. Optical input/outputs 502 receiver high speed serial datatransmission from another SeRF communicator. In addition, opticalinput/outputs 502 receive Open Base Station Architecture (OBSAI)protocol data from a baseband unit and/or a base station. In oneembodiment, to aid in the ability of optical input/outputs 502 toreceive multiple data formats, the signals received from opticalinput/outputs 502 are transmitted at the same frequency which is set tomatch the OBSAI protocol. Also, OBSAI data is stripped at the data linklayer with a 8B/10B encoder to provide a good ones and zeros balance andremove approximately 20 percent of the OBSAID overhead. Finally, 16-bitfiller words are used to provide a 24/25^(ths) transport ratio and matcha 2.94 GBps transport speed to enable transport of OBSAI or SeRF data.The OBSAI protocol data is explained in more detail below with referenceto FIG. 6. Optical input/outputs 206, also conform to the optical smallform-factor pluggable multi-source agreement. Alternatively, anyfrequency of signal or shape of connector could be used as is known inthe art. SeRF communicator 500 has eight (8) optical input/outputs andDART links 508 for 8 separate DART modules which transmit RF sampleddata to/from DART modules.

In one embodiment, DART links 508 and corresponding connectors on a DARTinterface carry 6 slots of digitized RF payload for reading and writingDART FPGA registers from SeRF FGPA 506. Each slot consists of 16 bits:15 bits of digitized RF and 1 overhead bit used to transfer FPGAregister data. The slots are framed in groups of 6 16-bit words, witheach slot repeating at the sampling rate of 15.36 M samples per second.A “superframe” of 32 frames encapsulates the data payload and providessynchronization. Thus, in this embodiment DART links 508 are 16-bitparallel data streams. In another embodiment, DART links 508 are serial.FPGA 506 has eight SERDES to serialize and de-serialize each datastream. Thus, there is one SERDES running for each DART link 508 andoptical input/output 502. In this embodiment, each SERDES runs at eitherhalf rate or full rate and 50% efficiency such that the SERDES offers 6RF slots of data. In another embodiment, there are half as many SERDESas DART modules. Thus, the SERDES run at full rate, 100% efficiency andoffer 12 RF slots of data.

In one direction, SeRF communicator 500 receives incoming SeRF streamsover DART links 508 from DART modules, assembles data frames, and sendsan outgoing optical serial data stream through optical input/outputs502. In the other direction, SeRF communicator 500 receives an opticalserial data stream from another SeRF communicator at opticalinput/outputs 502. SeRF communicator 500 then disassembles the frames ofthe serial data stream, and provides SeRF streams over DART links 508 toDART modules. SeRF communicator 500 also performs splitting and summingfor digital simulcast, and provides a user interface for alarm, status,or configuration management. SeRF communicator 500 also providesbi-directional conversion to/from OBSAI protocol data received atoptical input/outputs 502 from/to RF sampled data for DART modules.Additionally, SeRF communicator 500 has at least one RJ-45 connector 216for receiving IP packets. In one embodiment, RJ-45 connector 216supports Gigabit Ethernet.

Along with being configurable to communicate on different frequencyband/sub-bands and with different technologies, host unit 102 and remoteunit 106 are configurable to perform more or less of the wirelessprocessing of the RF signal. Host unit 102 and remote unit 106 areconfigurable into three different functional configurations. The firstconfiguration is illustrated in FIG. 1 and has host unit 101 and remoteunit 106 functioning as a range extender for base station 101. In thisconfiguration, backhaul data is transmitted between host unit 102 andremote unit 106. The second configuration is illustrated in FIG. 6, andhas fronthaul data transmitted between host unit 102 and remote unit106. In this configuration remote unit 106 performs the functionality ofa base station. The third configuration is illustrated in FIG. 7 and has‘midhaul’ data transmission between host unit 102 and remote unit 106.In this embodiment, ‘midhaul’ data refers to OBSAI protocol data orsimilar partially processed wireless signals. Each of the threeconfigurations will now be explained in further detail.

Referring back to FIG. 1, system 100 shows one configuration forconnection of host unit 102 and remote unit 106 in which remote unit 106functions as a range extender. In this option, base station 103 containsall necessary components to convert IP packets received from an Internetgateway into an analog bit stream for transmission over antenna 108.Except for needed amplification, the signal is ready for transmissionover antenna 108 once sent by base station 103. Host device 102 andremote device 106 do not perform any further processing on the dataexcept what is required to send and receive the data over long rangetransmission. Host unit 102 contains the components as illustrated inFIG. 2 and receives the analog signal from base station 103 at the DARTmodule matching the analog signal frequency band and technology. Hostunit 102 converts the signal and transmits the data over transportmechanism 104. Remote unit 106 contains the components as shown in FIG.3. Remote unit 106 receives the signal from transport mechanism 104 andsends the data to the DART module matching the frequency band andtechnology. The signal is then converted and transmitted over antenna108 to mobile users.

FIG. 6 shows another configuration of a system 100 where base stationfunctionality is performed at remote unit 106. This configurationprovides increased capacity to a network of antennas by allowing eachremote unit 106 to function as a base station. In this embodiment ofsystem 100, IP data is not processed by a base station before sending toremote unit 106. Instead IP data is received at host unit 102 directlyfrom IP gateway 101. IP data is received at an RJ-45 connector on SeRFcommunicator 202 of host unit 102. In this configuration, therefore, thesignal does not travel through DART module 208, 210, 212 of host unit102. The IP data is converted to a serial optical stream and transmittedover transport mechanism 104 to remote unit 106. Remote unit 106receives the IP data at SeRF communicator 302.

Remote Unit 106, in this embodiment, has a baseband unit 602 which isconnected to a slot of DART interface 306. In this configuration,baseband unit 602 is in fact a remote WiMax base station which replacesthe functionality of base station 103 in the first configuration. SeRFcommunicator 302 converts the packetized optical data received into25-75 Mbps data and sends the data over to baseband unit 602. Basebandunit 602 performs baseband processing to put the IP data onto a channel.Baseband unit 602 also creates the protocol and modulation type for thechannel. Baseband unit 602 then converts the data to match the OBSAIprotocol. This OBSAI data is sent back into an optical input/output 502of SeRF communicator 302. SeRF communicator 302 uses software to convertthe OBSAI protocol data into digital RF sampled data and sends thedigital RF data to DART module 308 for transmission over antenna 108. Inanother embodiment, baseband unit 602 converts IP data to/from commonpublic radio interface (CPRI). Alternatively, any digital basebandprotocol, including standard and proprietary protocols, or any softwaredefined radio interface could be used by baseband unit 602 and SeRFcommunicator 302.

FIG. 7 illustrates yet another configuration of a system 100 in whichremote unit 106 performs the functionality of a base station, and thebaseband processing is performed prior to transmission by host unit 102.In this embodiment, IP data is received at a baseband unit 702 whichconverts the IP data into data conforming to the OBSAI protocol. Inanother embodiment, OBSAI protocol data is communicated between SeRFcommunicator 202 and a base station 103 as shown in FIG. 1.Alternatively, any of the protocols listed with respect to FIG. 6 couldbe used. The OBSAI protocol data is converted to serial data in SeRF 202of host unit 102 before the serial data is transmitted to remote unit106. Here again, DART module 208 is not used at host unit 102, since thedata has not been converted to RF yet. The OBSAI protocol data isreceived by remote device 106 at SeRF communicator 302. SeRFcommunicator 302 converts the OBSAI protocol data into digital RFsampled data and interfaces with DART 308. DART 308 converts the data toanalog RF and the signal is sent over antenna 108.

Since host unit 102 and remote unit 106 have multiple input/outputs andcan have multiple types of DART modules connected to each, host unit 102and remote unit 106 are configured to multiplex different functionalconfigurations through different input/outputs simultaneously. Thus, inone embodiment, a first input/output of host unit 102 and remote unit106 function as a range extender for a base station. A secondinput/output of host unit 102 and remote unit 106 function to transmit‘midhaul’ data. At the same time a third input/output of host unit 102and remote unit 106 functions to transmit fronthaul data and remote unit106 performs baseband processing upon the data.

The modular design of modular wireless communications protocol allowsmany different combinations of transport mechanisms, frequency bands,communication technologies, and processing functionality to operatesimultaneously on the same host unit and remote unit.

Placing a base station at a remote wireless communication stations suchas described with the configuration of FIG. 6 allows service providersto set up a distributed base station system. FIG. 8 illustrates oneembodiment of a distributed base station system 800. System 800 has acentral node 801 having an IP gateway and a plurality of remote wirelesscommunication stations 802, 804, 806, 808, 810, 812. Each remote station802, 804, 806, 808, 810, 812 includes a remote unit 814, 816, 818, 820,822, 824, an antenna 826, and a router 828. In this embodiment, remoteunit 818 and remote unit 820 are configured into a WiMax compatible basestation. In another embodiment, all remote units 814, 816, 818, 820,822, 824 are configured into PCS cellular base stations. Alternatively,any number of remote units 814, 816, 818, 820, 822, 824 could beconfigured into a base station for any of the technology or frequencybands described with respect to system 100. Each remote station 802,804, 806, 808, 810, 812 functions similarly, except that they will varybased on the configuration of their respective remote unit 814, 816,818, 820, 822, 824.

Distributed base station system 800 has many advantages over traditionalcentralized base station systems. For example, remote stations 806, 806which are equipped with a base station do not need to transmit signalsback to central node 801 for base station processing. Instead, when anRF signal is received via antenna 826 at remote station 806, forexample, remote station 806 processes the RF signal with remote unit818, which is configured as a base station. Processing the RF signalforms a second RF signal which is then routed toward the destination ofthe RF signal. In this embodiment, the RF signal received at remote unit806 is from a first mobile device which is in communication with asecond mobile device which is the destination of the second RF signal.In another embodiment, the RF signal is received from a fixed internetuser and the destination of the second RF signal is on the internet viaIP gateway at central node 801. In this embodiment, the second mobiledevice is within transmission range of remote station 812. Thus, afterprocessing by remote unit 818 at remote station 806, routers 828 atremote stations 806, 810, 812 route the second RF signal through remotestation 810 to remote station 812. Thus, distributed base station system800 simplifies and speeds up the processing of wireless signals.

In addition, there are many other advantages of a distributed basestation system. For example, since each remote station 802, 804, 806,808, 810, 812 includes a router, a best path is found to the from theorigination remote station to the destination remote station. Thisdecreases the latency of communication transmission, and also reducesunnecessary network traffic. In addition, in one embodiment where eachremote station 802, 804, 806, 808, 810, 812 is equipped with a basestation, each remote station 802, 804, 806, 808, 810, 812 obtainsdedicated capacity to the system. Dedicated capacity refers theallocation of an unvarying amount of bandwidth to each remote station802, 804, 806, 808, 810, 812. For example, in one embodiment, eachremote station 802, 804, 806, 808, 810, 812 is allocated 25 Mbps ofbandwidth. This is not possible in previous systems, because each remotestation shares the capacity of a single central base station.

In one embodiment, remote stations 802, 804, 806, 808, 810, 812 are setup in a ring configuration as shown in FIG. 8. The ring structure isadvantageous, because a ring configuration allows multiple paths to befound to each remote station 802, 804, 806, 808, 810, 812. Thus, thereare more options for a best path to be found to each remote device 802,804, 806, 808, 810, 812, and congested areas are more easily avoided. Inanother embodiment, shown in FIG. 9, remote stations 902, 904, 906, 908,910, 912 are arranged into tree configurations. Tree configurations areadvantageous, because they reduce the complexity of the network and theamount of communication links that must be established. Treeconfigurations, however, still provide reduced latencies by allowingsignals to be routed through the local hubs (e.g. remote station 902 and908) and not requiring transmission to central hub 901.

In yet another embodiment, a plurality of remote stations is set up in adaisy chain configuration. Alternatively, any combination of ring, tree,or daisy chain configurations could be used to network a plurality ofremote stations.

Although specific embodiments have been illustrated and describedherein, it will be appreciated by those of ordinary skill in the artthat any arrangement, which is calculated to achieve the same purpose,may be substituted for the specific embodiment shown. This applicationis intended to cover any adaptations or variations of the presentinvention. Therefore, it is manifestly intended that this invention belimited only by the claims and the equivalents thereof.

1. A distributed antenna system, comprising: a host unit that includes:an interface adapted to communicate RF signals with an Internet Protocol(IP) gateway as IP data; a baseband processor, coupled to the IPgateway, the baseband processor configured to convert between IP dataand baseband, digital signals; and a serializer/deserializer, coupled tothe baseband processor, the serializer/deserializer configured toconvert between baseband, digital data and a serial data stream; and aremote unit, coupled to the host unit over a communication medium, theremote unit including: a serializer/deserializer, coupled to thecommunication medium, the serializer/deserializer configured to convertbetween the serial data stream and RF sampled data; an RF module,coupled to the serializer/deserializer, the RF module configured toconvert between RF sampled data and an RF signal; and an antenna coupledto the RF module.
 2. The distributed antenna system of claim 1, whereinthe serial data stream comprises a first serial data stream; wherein thehost unit includes: an RF module coupled to a base station andconfigured to convert between RF signals configured for communicationover an antenna and RF sampled data; wherein the serializer/deserializerof the host unit is further configured to: convert between RF sampleddata and a second serial data stream.
 3. The distributed antenna systemof claim 2, wherein the host unit includes: a multiplex moduleconfigured to multiplex and demultiplex the first serial data stream andthe second serial data stream for concurrent communication over thecommunication medium; and wherein the remote unit includes: a multiplexmodule configured to multiplex and demultiplex the first serial datastream and the second serial data stream for concurrent communicationover the communication medium.
 4. The distributed antenna system ofclaim 2, wherein the serializer/deserializer of the host unit is coupledto the IP gateway and is further configured to convert between IP dataand a third serial data stream; wherein the serializer/deserializer ofthe remote unit is further configured to convert between the thirdserial data stream and IP data; wherein the remote unit includes abaseband processor, coupled to the serializer/deserializer of the remoteunit, the baseband processor configured to convert between IP data andbaseband, digital data, wherein the serializer/deserializer of theremote unit is further configured to convert between the baseband,digital data and RF sampled data.
 5. A remote unit of a distributedantenna system, the remote unit comprising: a serial interfaceconfigured to receive a serial data stream from a host unit over acommunication medium; a serializer/deserializer, coupled to the serialinterface, the serializer/deserializer configured to convert between theserial data stream and Internet Protocol (IP) data; a basebandprocessor, coupled to the serializer/deserializer, the basebandprocessor configured to convert between IP data and baseband, digitaldata; wherein the serializer/deserializer is further configured toconvert between baseband, digital data and RF sampled data; and an RFmodule, coupled to the serializer/deserializer, the RF module configuredto convert between RF sampled data and an RF signal.
 6. The remote unitof claim 5, wherein the serial data stream includes first serial datacorresponding to IP data and second serial data corresponding tobaseband, digital data or RF sampled data; wherein remote unit comprisesa multiplex module configured to multiplex and demultiplex between theserial data stream and the first and second serial data; and wherein theserializer/deserializer of the remote unit is further configured toconvert between second serial data and RF sampled data.
 7. The remoteunit of claim 6, wherein the RF module is a first RF module, the firstRF module configured to communicate with mobile devices using a firstfrequency band; wherein the remote unit includes a second RF module,coupled to the serializer/deserializer, the second RF module configuredto convert between RF sampled data and an RF signal, wherein the secondRF module is configured to communicate with mobile devices using asecond frequency band; and wherein the serializer/deserializer isconfigured to communicate RF sampled data corresponding to the firstdata stream with the first RF module and to communicate RF sampled datacorresponding to the second data stream with the second RF module.
 8. Amethod for transporting RF communications, the method comprising:receiving a first RF signal at a host unit as first internet protocol(IP) data; converting the first IP data to a first baseband, digitalsignal; converting the first baseband, digital signal to a first serialdata stream; transporting the first serial data stream to a remote unit;converting the first serial data stream to a second RF signal; andtransmitting the second RF signal at the remote unit.
 9. The method ofclaim 8, comprising: receiving a third RF signal at the host unit as asignal configured for communication over an antenna; converting thethird RF signal to a second serial data stream; multiplexing the secondserial data stream with the first serial data stream; transporting thesecond serial data stream to the remote unit; demultiplexing the secondserial data stream from the first serial data stream; converting thesecond serial data stream to a fourth RF signal; and transmitting thefourth RF signal at the remote unit.
 10. The method of claim 8,comprising: receiving a fifth RF signal at the host unit as second IPdata; converting the second IP data to a third serial data stream;multiplexing the third serial data stream with the first serial datastream; transporting the third serial data stream to the remote unit;demultiplexing the third serial data stream from the first serial datastream; generating a second baseband, digital signal from the thirdserial data stream; converting the second baseband, digital signal to asixth RF signal; and transmitting the sixth RF signal at the remoteunit.
 11. A method for transporting RF communications, the methodcomprising: receiving a first RF signal at a host unit as first internetprotocol (IP) data; converting the first IP data to a first serial datastream; transporting the first serial data stream to a remote unit;generating a first baseband, digital signal from the first serial datastream; converting the first baseband, digital signal to a second RFsignal; and transmitting the second RF signal at the remote unit. 12.The method of claim 11, comprising: receiving a third RF signal at thehost unit as a signal configured for communication over an antenna;converting the third RF signal to a second serial data stream;multiplexing the second serial data stream with the first serial datastream; transporting the second serial data stream to the remote unit;demultiplexing the second serial data stream from the first serial datastream; converting the second serial data stream to a fourth RF signal;and transmitting the fourth RF signal at the remote unit.
 13. The methodof claim 11, comprising: receiving a fifth RF signal at the host unit assecond internet protocol (IP) data; generating a second baseband,digital signal from the second IP data; converting the second baseband,digital signal to a third serial data stream; multiplexing the thirdserial data stream with the first serial data stream; transporting thethird serial data stream to the remote unit; demultiplexing the thirdserial data stream from the first serial data stream; converting thethird serial data stream to a sixth RF signal; and transmitting thesixth RF signal at the remote unit.
 14. A distributed antenna system,comprising: a host unit that includes: an RF module configured tocommunicate with a base station using RF signals configured forcommunication over an antenna, the RF module configured to convertbetween the RF signals configured for communication over an antenna andRF sampled data; a serializer/deserializer coupled to the RF module andconfigured to communicate with a base station using signalscorresponding to baseband, digital data, the serializer/deserializerconfigured to convert between RF sampled data and first serial data andconfigured to convert between baseband, digital data and second serialdata; and a multiplex module coupled to the serializer/deserializer, themultiplex module configured to multiplex the first serial data and thesecond serial data into a high speed serial data stream and todemultiplex a high speed serial data stream into the first serial dataand the second serial data; a remote unit, coupled to the host unit overthe communication medium, the remote unit configured to convert the highspeed serial data stream into one or more RF signals.
 15. Thedistributed antenna system of claim 14, wherein the remote unitincludes: a multiplex module configured to demultiplex the high speedserial data stream into the first serial data and the second serial dataand to multiplex the first serial data and the second serial data into ahigh speed serial data stream; a serializer/deserializer coupled to themultiplex module, the serializer/deserializer configured to convertbetween the first serial data and first RF sampled data; an RF modulecoupled to the serializer/deserializer and configured to convert betweenthe first RF sampled data and an RF signal for communication over anantenna; and an antenna coupled to the RF module.
 16. The distributedantenna system of claim 15, wherein the serializer/deserializer of theremote unit is configured to convert between the second serial data andsecond RF sampled data; wherein the remote unit includes: another RFmodule coupled to the serializer/deserializer and configured to convertbetween the second RF sampled data and an RF signal for communicationover the antenna.
 17. The distributed antenna system of claim 14,wherein the baseband, digital data corresponds to one of an open basestation architecture (OBSAI) protocol or a common public radio interface(CPRI) protocol such that the serializer/deserializer of the host unitis configured to communicate with a base station using signalscorresponding to one of the OBSAI protocol or the CPRI protocol and theserializer/deserializer of the host unit is configured to convertbetween signals corresponding to one of the OBSAI protocol or the CPRIprotocol and the second serial data.
 18. A host unit of a distributedantenna system comprising: an RF module configured to communicate with abase station using RF signals configured for communication over anantenna, the RF module configured to convert between the RF signalsconfigured for communication over an antenna and RF sampled data; aserializer/deserializer coupled to the RF module and configured tocommunicate with a base station using signals corresponding to baseband,digital data, the serializer/deserializer configured to convert betweenRF sampled data and first serial data and configured to convert betweenbaseband, digital data and second serial data; a multiplex modulecoupled to the serializer/deserializer, the multiplex module configuredto multiplex the first serial data and the second serial data into ahigh speed serial data stream for transmission over a communicationmedium and to demultiplex a high speed serial data stream from thecommunication medium into the first serial data and second serial data.19. The host unit of claim 18, wherein the baseband, digital datacorresponds to one of an open base station architecture (OBSAI) protocolor a common public radio interface (CPRI) protocol such that theserializer/deserializer is configured to communicate with a base stationusing signals corresponding to one of the OBSAI protocol or the CPRIprotocol and the serializer/deserializer is configured to convertbetween signals corresponding to one of the OBSAI protocol or the CPRIprotocol and the second serial data.
 20. A method for transporting RFcommunications, the method comprising: receiving a first RF signal froma base station at a host unit, the first RF signal configured fortransmission from an antenna; receiving a first baseband, digital signalfrom a base station at a host unit; converting the first RF signal tofirst serial data; converting the first baseband, digital signal tosecond serial data; multiplexing the first serial data with the secondserial data to form a high speed serial data stream; transporting thehigh speed serial data stream to one or more remote units;demultiplexing the high speed serial data stream to obtain the firstserial data and the second serial data; converting the first serial datato a second RF signal; transmitting the second RF signal at the one ormore remote units; converting the second serial data to a third RFsignal; and transmitting the third RF signal at the one or more remoteunits.
 21. The method of claim 20, wherein receiving a first baseband,digital signal includes receiving a signal conforming to one of an openbase station architecture (OBSAI) protocol or a common public radiointerface (CPRI) protocol; and wherein converting the first baseband,digital data includes converting signals conforming to one of the OBSAIprotocol or CPRI protocol to the first serial data.
 22. The method ofclaim 20, comprising: receiving a fourth RF signal at a host unit froman IP gateway, the fourth RF signal including first IP data; generatinga second baseband, digital signal from the first IP data; converting thesecond baseband, digital signal to third serial data; multiplexing thethird serial data with the first and second serial data to form the highspeed serial data stream; demultiplexing the high speed serial datastream to obtain the third serial data; converting the third serial datato a fifth RF signal; and transmitting the fifth RF signal at the one ormore remote units.
 23. The method of claim 20, comprising: receiving asixth RF signal at a host unit from an IP gateway, the sixth RF signalincluding second IP data; converting the second IP data to fourth serialdata; multiplexing the fourth serial data with the first and secondserial data to form the high speed serial data stream; demultiplexingthe high speed serial data stream to obtain the fourth serial data;generating a third baseband, digital signal from the fourth serial data;converting the third baseband, digital data to a sixth RF signal; andtransmitting the sixth RF signal at the one or more remote units.